Classification and Quantitative Modeling Analysis of Groundwater Hardness based on Ultraviolet Absorption Spectrum

Abstract

In accordance with the national standard of groundwater quality, samples with various ion concentrations are prepared based on water hardness standard substances, and a water hardness classification and quantitative analysis model based on ultraviolet absorption spectrum are established. Firstly, thepartial least squares discriminant analysis (PLSDA) model is established by using a group of samples with different ion concentration that form the training set, and the binary tree is introduced for multiple classification of water hardness. Secondly, partial least squares support vector machine (PLS-SVM) is used to establish the quantitative model of each class of samples. Atlast, Monte carlo cross-examination is performed on the model using a test set composed of samples with different ion concentrations. Experimental results show that, for the identification of underwater hardness, the average error rate is 1.13%, which is less than other common classification methods, and MSE is 0.247, and R2 is 0.987, which both are improved than other common methods for the prediction of ion concentration of underwater.